Abstrac t Opioid misuse is a major public health issue among young adults in the United States and is an especially acute problem in rural communities. Critically, prevention efforts for opioid misuse that serve young people often do not effectively involve them. Prevention organizations would benefit from an effective youth engagement strategy to incorporate the voices of young people in planning prevention programs and policy. Further, young adulthood is a formative time for positive social development; but unfortunately, many young people feel isolated within communities, feel that they do not matter, and lack meaningful opportunities to engage with society and form positive connections with prosocial institutions. Prevention organizations lack evidence-based strategy to marshal the considerable resources that young adults can bring to strengthening prevention efforts by increasing their meaning and relevance for young adults; at the same time, young adults may be at risk for opioid misuse in part due to isolation and lack of meaningful opportunities for engagement in their communities. Engaging young people to contribute to the prevention organizations targeting substance use may prevent opioid misuse by targeting two pathways: (1) an environmental pathway whereby young adults affect community systems and settings through improving prevention efforts and (2) an individual pathway bolstering psychosocial protective factors and reducing risks for the young adults engaged in prevention efforts. Aligned with NIDA's HEAL initiative and the 2016-2020 strategic plan Objective 2.2, this K01 proposal seeks to elucidate the environmental and individual pathways through which youth engagement can prevent opioid misuse. The research component of this mentored career development award will develop and test an organization-level prevention strategy for effectively integrating meaningful youth engagement opportunities into multi-component prevention efforts. The project will identify which community-based prevention organizations, and which subset of young adults, would most benefit from youth engagement as a strategy for preventing opioid misuse (Aim 1); develop an organization-level youth engagement prevention strategy and implement it with one community-based organization to test feasibility and acceptability (Aim 2); and evaluate the preliminary effectiveness of youth engagement as an organization-level strategy for preventing opioid misuse in a small pilot randomized controlled trial (Aim 3). The training component of this award will allow me to develop critical skills in (1) community-based systems and settings for substance use prevention targeting vulnerable young adults; (2) opioid misuse among young adults in rural settings; (3) prevention intervention development; and (4) randomized clinical trials research. With guidance from an outstanding mentor team, this K01 will fully prepare me to become an independent investigator with the skills to carry out research yielding much-needed new strategies to mitigate the societal issue of opioid misuse among young adults.